1. Field of the Invention
This invention relates to a printing apparatus in which intermediate hammers and a stain preventing member can be shifted by a simple mechanism.
2. Description of the Prior Art
Generally, in an impact printer having a plurality of columns wherein a character drum is rotated and hammers are energized in synchronism with characters to be printed to thereby effect printing, the hammer mechanism directly driven by solenoids has required a great magnitude of electric power for the driving. Therefore, the power source has been of a greater capacity as the number of columns has been increased.
Further, when a plurality of columns is printed on a web of paper having a predetermined width, the column pitch becomes smaller and so, it has become difficult in terms of space to provide a hammer for each column.
Therefore, consideration has been given to a technique of decreasing the number of hammers to half by providing intermediate hammers between hammers and a character drum and shifting the intermediate hammers by one column pitch to enable printing of two columns by one hammer.